US First Lady Michelle Obama and her daughters, Sasha and Malia with Dr Patrick Prendergast, President and Provost of Trinity College Dublin, during their visit to view the Book of Kells and archives documenting the Obama’s Irish ancestry. Photograph: Cyril Byrne / THE IRISH TIMES

In the first stop of their visit to the Republic, Mrs Obama visited the Old Library with her daughters Malia, who will turn 15 next month, and Sasha, who celebrated her 12th birthday last week. They arrived in Dublin just before noon, having flown into Belfast earlier with the US president Barack Obama. He travelled to Co Fermanagh for the G8 summit.

Fiona Fitzsimons and Helen Moss of Eneclann, a university spin-out company researched President Obama’s Irish ancestry from Falmouth Kearney, president Obama’s second great-grandfather to his seventh great-grandfather, Joseph Kearney. John Kearney, who was a distant cousin of the president, went on to become the Provost of Trinity College Dublin, and later Church of Ireland Bishop of Ossory.

Ms Fitzsimons showed the family tree to the Obamas. “It’s a family history that goes back a very, very long way,” she said afterwards. “We can actually say more, with absolute certainty, about the Irish ancestry of the Obamas than we can for figures like JFK or Ronald Reagan or even Bill Clinton.” She said the teenage girls were absolutely delightful. “The girls are obviously very close to their mum. They were asking loads of questions.”

The Obamas signed the visitors’ book, Sasha using her full name Natasha M. Obama. Their viewing of the Book of Kells means that it will be in more demand than ever this summer. Trinity’s visitor services manager Anne-Marie Diffley was one of the people showing the first family around the Old Library and she said they were very enthusiastic guests.

“She [Mrs Obama]was very warm and very interested. The girls were like normal teenagers. They were interested and asking questions and looking around.” The Obamas were presented with several gifts including an illustrated children’s book about Trinity College called This is Trinity by Claire Kamber. “I am thrilled to tiny little bits,” the artist and writer said afterwards.

Trinity Provost Dr Patrick Prendergast told the Obamas it was a honour to have them at the university. “As a country, America has welcomed many of our graduates over the years where a large number of our alumni are living. Our graduates who play a critical role in shaping the knowledge economy are our diaspora,” he added.

A large crowd gathered at the front gates of Trinity College, hoping to catch a glimpse of the first family. After waiting an hour, they were rewarded when the fleet of armoured cars exited onto College Green. While it was difficult to see the First Lady through the darkened glass, Brendan Higgins from Donabate said it was worth the wait. “At least we tried,” he said. Jennifer Ndukwe was delighted. “I just took so many pictures because there were so many black cars and I didn’t know which one they were in,” she said. “It’s good for the country after so much misery. It might cheer people up.”

The Obamas then paid a private visit to the US Embassy where they met staff and their families. Later they attended the Gaiety Theatre for a special performance of Riverdance. They were accompanied by Sabina Higgins, wife of the President Michael D Higgins, Fionnuala Kenny, wife of Taoiseach Enda Kenny and a group of Irish teenagers, including some from Moneygall, where Mr Obama’s ancestors lived. They are due to stay in the Shelbourne Hotel on Dublin’s St Stephen’s Green tonight. Tomorrow they will travel to Glendalough before departing for Berlin.

Earlier the Obamas were welcomed at Dublin Airport by Tánaiste Eamon Gilmore and his wife Carol Hanney. The welcoming party also included the Dublin Lord Mayor Naoise Ó Muirí, his wife Fionnuala Keane and officials.